New Tungsol KT120 output tube for Dynaco amps - first impressions on 4/16/10

Thank's Bob

I have had the amp sens Aug 09 i have the sovtek power tubes in it now and one will not bias. But i have had three quads of the gold lions from guitar center(they ship the tubes with no extra packaging) and they never lasted more than two to three months. I run the amp about 10 to 12 hours a day.I am looking for a good place to get the eight gold lions & four sovtek's tested, seams when they go they like to take the rectifier with it.(I'm getting very good at rebuilding the copper caps). So i ordered kt-120 and I'm hoping that they will last longer. I have a 1951 st-70 that has tubes that are older then me(1953)that plays out in the shop.So I'm wondering how long do the power tubes last on average in a st-120 at reasonable to reasonably loud play? I have Denon avr 3806 as the preamp and crossover 95Hz to sunfire CRM2s as the mains on the st-120.

Thank's
Mike B.

Hi:
What diodes are you using to rebuild the copper caps if you changed them or did you just change the resistors and are you replacing the thermistor as well?
I rebuilt a WX68 and changed all the parts but used the stock parts values and it seems to be fine. I am wondering which parts are prone to failure. Of course the resistors were fried but I wonder if some of the other parts are also damaged when they blow? Is it possible to change the resistor value for a little more durability.

I have rebuilt one four time's with only the resistors needing to be replaced.

Hi Avi:
That's kind of my point you had to build it 4 times. I am thinking that the diodes are a little fried. Mine is still working after 6 months. Diodes can be damaged by heat and those things get quite hot. Still there are a lot of other things that can blow them.
Baddog1946